Translating device



Ot. 9, 1928.J 1,687,231

J. B. SPEED TRANSLATING DEVICE Filed NOV. 19, 1924 @JPM Patented Oct. 9,1928.

UNITED STATES PATENT orties.

JAMES BUCKNER SPEED, OF NEW YORK, N. Y., .ASSIGNOR TO WESTERN ELECTRICCOM- PANY, INCORPORATED, 0F NEW YORK, N. Y., A CORPORATION OF NEV YORK.

TRANSLATNG DEVICE.

Application filed November 19, 1924. Serial No. 750,738.

This invention relates to translating de' vices and more particularly todevices for interconverting electrical and sound energy.

An object ot the invention is directly to convert sound energy intoelectrical energy and electrical energy into sound energy.

This object is accomplished by utilizing the etl'ect upon the dielectricconstant ot an air condenser of raretactions and condensations olf theair between the plates and the etlect ot' diil'erences of impressedpotential between the plates on the pressure oit' the air between them.

Another object of the invention is to construct a substantiallyspherical air condenser by means ot which sound energy may be receivedfrom or transmitted in all directions.

A condenser of this form may be obtained by assembling a plurality oi'condenser units, made of metal plates formed into trapezoidal shapedwedge cells, combining a plurality ot' these units to form anapproximately spherical triangular section having a ridge parallel toeach leg of the triangle, and uniting several triangular sections toform a .substantially spherical body, each unit having its platesextending in a generally radial direction trom the center ot the sphere.

Referring now to the drawings, Fig. 1 illustrates a substantiallyspherical condenser.

constructed in accordance with the invention.

Fig. 2 illustrates in perspective a pair ot wedge shaped units of whichthe condenser is formed, and

Fig. 3 illustrates schematically one embodiment ot the invention used asa transmitter..A

This invention contemplates the use of an air condenser of sufficientlysmall dimensions that the space between adjacent plates may be entirelyiilled or emptied at any one time of either condensation or rarefactionof sound w,aves,thereby changing its dielectric constant, due to thecompression or expansion of the air. Tn this way, the capacity of thecondenser is changed and there results a change of potential between thecondenser plates which may be used to change the potential impressedupon a vacuum tube ampliier circuit to accomplish the liberation ofelectrical energy in an ordinary telephone circuit in .a quantitysuiicient to reproduce the sound waves `by any ordinary reproducingdevice.

The minute changes of pressure between the plates, however, result in atoo small change of capacity to be utilized directly.

Therefore, 4in one embodiment ot the invention, use is made ot' aYWheatstone bridge arrangement having an air condenser in each arm. Thecondensers in two parallel arms of the bridge are enclosed in soundprooi' compartments and the other pair are exposed to the speech Wavesto be transmitted. This arrangement provides a balanced bridge by meansof which the capacity of the exposed condensers will be higher'orlower'than that ot' the enclosed condcnsers when a speech wave isimpressed thereon. By supplying to two opposite terminals of the bridgea high 'frequency circuit land connecting the remaining two terminals toa telephone circuit or the like, speech waves impressed upon thecondensers cause a flow of current alternately across the bridge tomodulate the high trequency current, the modulated wave beingtransmitted over the telephone line to .a demodulating deviceassociatedwith a receiver whereby the sound impressed upon thecondensers may be reproduced.

-ltelerring now particularly to Fig. 3, the condensers 10, 11, 19. and13 are connected in the parallel arms ot a Wheatstone bridge, thecondensers 12 and 13 being enclosed in sound prootl compartments 14 and15, respectively. The terminals 16 and 17 ofthe bridge are connected tothe output circuit o`' a distortionless amplifier 18, the input circuitot which is connected through the transformer 19 with a vacuum tubeoscillator 2O for supplying .high frequency alternating current to theWheatstone bridge. A variable condenser 21 may be inserted in one of theleads i'rom the ampliler to tune the VVhoatstone bridge to the frequencysupplied by the oscillator 20. An induction coil 22 is inserted in eacharm of the bridge adjacent the condenser to main- U tain the individualarms near but not quite at their resonance point.

The terminals 23 and Q4 otl the VVheatstone bridge are connected bywires Q5 and 26 to a vacuum tube dcmodulator Q, the output circuit ofwhich is connected to any suitable reproducing device such as thereceiver 284 through a transformer 29.

Itis evident that the hightrequency potential impressed on the bridgecan be modulated by changes in the dielectric constant of the uncoveredcondenser-s, due to the impression ot speech waves thereon. Theresultant modulated current is impressed on the demodulator 27 toproduce corresponding 10W frequency lOll currents having a substantiallyflat transmission characteristic. In this manner there may bereproduced-in the receiver 28, the sound waves impressed upon theuncovered condensers.

In order that sound waves may be freely transmitted in or received fromall directions, this invention contemplates the use of a substantiallyspherical condenser having its plates approximately radial thereof. Thecondenser is composed of a large number of wedge shaped condenser unit-sso designed that they l,nay be combined to form the condenser body. Eachunit is composed of a plurality of plates 30 of metal of trapezoidalshape and of graduated dimensions. These plates are equally spaced andtwo groups of plates have one set of non-parallel edges embedded in amolded partition 31 thereby forming a wedge shaped unit as shown in Fig.2. These units, however, may be made up of a single set of platesinstead of two sets, in which case each plate will have dimensionscorresponding to two of the smaller plates Each plate is provided with atab 32 by means of which conductors may be connected thereto to connectthe alternate plates in series.

These units are combined to form a triangular section 33 by taking threesets of wedge shaped units, as shown in Fig. 2, and arranging them withthe shorter parallel leg in contact with the oblique leg of a second setand the longer of the parallel legs in alignment with the oblique leg ofthe third set so that the planes of the plates of each set are at anangle with respect to the' planes of the plates of each other set, theintersection of the shorter parallel legs lying beyond the plane of thevertices of the triangle. Preferably, twent of these triangular sectionsare united wit their edges lying approximately on the arc of a greatcircle of a sphere thereby forming a lsubstantially spherical body. Theplanes of the plates of the individual units extend substantiallyradially of the spherical body thereby permitting transmission andreception of sound waves in all direction.

To obtain the dimensions necessary for the trapezoidally-shaped c`ell, aspherical surface of the desired size is divided into twenty 20) equaltriangles, in which the?. apices of t ese triangles are also the apiceso sin icosahedron, 1, and each side of each of the spherical triangles!vi lies on the arc of a great circle. The spherical triangle is furthersubdivided by cutting thetriangle into three equal segments, that is, bydrawing three lines 120 apart from the centre of the triangle andorienting the lines so that they are parallel with the sides of thetriangle. Since the surface of the triangle lies on the arc of a greatcircle, the converging points of the trapezoidal segments are above theplane of the apices of the triangle, and the plane of the segment may beobtained by cutting the spherical surface in a planary line with thesides o-f the trapezoidal segment. This subdivision results in a'substantially spherical body having sixty (60) equal trapezoidal cellswhich may be further divided by cutting the trapezoidal cell in halfwhereby one hundred and twenty (120) surfaces may be obtained.

i This arrangement provides an easily manufactured condenser, thesurface of which comprises a large number of faces of uniform shape andarea. As the shape of the condenser units is uniform and dimensionssimilar, the manufacture thereof is comparatively simple andinexpensive. The resultant body, although not a regular polyhedron, yetcomprises a polyhedron having a large number of substantially similarand equal faces.

Although the invention has been described as applied to a special formof condenser transmitter, it is apparent that the principles of theinvent-ion may be utilized in converting electrical energy to soundenergy by varying the potentials between the plates of an air condenserto produce rarefactions and condens'ations of the air between theplates. Also the particular method of constructing a polyhedrom having alarge number of uniform faces is not limited to the building of acondenser but may be of general application. This method makes possiblethe construction of a nearly regular polyhedron of a larger number offaces than an icosahedron, that is, a polyhedron of 60 or of 120 equalfaces, but each face is, however, not a regular polygon such as atriangle, square or pentagon, Lbut is a trapezoid.

It is, of course, understood that various modifications may be madewithout in any way departing from the scope of the invention as delinedin the appended claims.

What is claimed is:

1. A translating circuit comprising an air condenser, means to impress adifference of potential between the` plates of said condenser and anoutput circuit connected to said condenser, the spaces between theplates being sufficiently small that the air pressure therein may bevaried by sound waves impressed upon the air between the plates wherebythe capacity of the condenser is varied to convert the impressedsoundwaves into electrical vibrations in said output circuit.

2. A translating. circuit comprising anair condenser, means to impresshigh frequency electrical vibrations between the plates of saidcondenser and an output circuit connected to said condenser, the spacesbetween the plates being sufficiently small that the air pressuretherein may be varied by sound waves impressed upon the air between theplates whereby the capacity of the condenser is' varied to modulate theelectric vibrations in accordance with the impressed sound waves.

3. A translating circuit comprising a Wheatstone bridge, an aircondenser 1n each arm of said bridge, means for impressing highfrequency electrical vibrations upon two oppo-site terminals ofsaid'bridge and an output circuit connected to the other terminals ofsaid bridge, the spaces between the plates of said condensers beingsufficiently small that the air pressure therein may be varied by soundwaves impressed thereon whereby the capacity of the condenser is variedto modulate the high frequency electrical vibrations in accordance withthe impressed sound waves.

4:. A- translating circuit comprising a Wheatstone bridge, lan aircondenser in each arm of said bridgemeans for impressing high frequencyelectrical vibrations upon two opposite terminals of said bridge, anoutput circuit connected tothe other terminals of said bridge and soundproof compartments enclosing the condensers in two opposite arms, thespaces between the plates of said condensers being sufficiently smallthat the". air pressure therein may be varied by sound waves impressedthereon whereby the capacity of the condensers is varied to modulatesaid electrical vibrations in accordance with the impressed sound waves.

5. A translating circuit.- comprising a Wheatstone bridge, asubstantially spherical condenser in each arm of said bridge, means forimpressing high frequency electrical vibrations'upon two oppositeterminals of said bridge, and an output circuitv connected to the otherterminals of said bridge, each of said condensers having the spacesthereon radially arranged and sufficiently close that the air pressuretherebetween may be varied.

by sound waves impressed thereon whereby the capacity of the condensersis varied to modulate the electrical vibrations in accordance with theimpressed sound waves.

6. A vtranslating circuit comprising a Wheatstone bridge, a sound proofcompartment enclosing the condenser-s in two opposite arms of saidbridge, means for impressing high frequency electrical vibrations upontwo opposite terminals of said bridge, and,

an output circuit connected to the other terminals of said bridge, eachof said condensers having the spaces thereon radially arranged andsufficiently close that the air pressure therebetween may be varied bysound waves impressed thereon whereby the capacity of the condensers isvaried to modulate the electrical vibrations in accordance with theimpressed sound waves.

7. A translating system comprising a pair of condenser .transmitters thecapacity of which is variable under control of sound vibrations in theair, a pair of condensers shielded from the effects of sound vibrations,a Wheatstone bridge including said pairs of condensers in respectivelyopposite arms so that each two adjacent arms include a condenser of eachof said pairs, a source of' high frequency waves connected in onediagonal of said bridge, and a detector and receiver .connected in theother diagonal, each armof said bridge containing inductance of a valueto make each arm nearly resonant at the frequency of .said wave source.

In witness whereof, I hereunto subscribe my name this 14th day ofNovember, A. D. 75

JAMES BUCKNER SPEED.

